I am a new contact lens wearer. They have been going well, not problems putting in or taking out. Trouble today however is that when I went to remove them, one seems to have disappeared. Please would seasoned wearers let me know if they can fall out. I have tried to look under my lids and roll my eyeball around but I can not see or feel anything anywhere in there. Could it be tucked way under without me feeling it? Has it fallen out? Can that even happen?